DE29500115U1 has disclosed a clamping element, by way of which a load can be fixed in a bore of a component. To this end, a plurality of part shells which are held together by way of O-rings interact with a clamping element. By means of a disc spring assembly, the clamping element is pressed into the part shells for bracing purposes and in this way braces said part shells against the inner wall of the bore with a constant force. The load which is attached to the clamping element is as a rule at a certain spacing from the component, however, after the bracing action. After the bracing action, the load (as a rule, a holder or a holding plate for a mobile machine) is moved up to the component by means of a hydraulically actuated mechanism. This ensures a complete contact between the load and the component. In this way, the effect of the vibrations which are caused by way of the mobile machine on the bracing action is to be reduced.
It is a disadvantage in said prior art that, during the positioning of the clamping element in the bore, the centring action is achieved only with a comparatively great play. In addition, the part shells of the clamping sleeve have to be of stable configuration on account of the selected construction, in order that the respectively acting forces of the bracing action can be introduced into the clamping element. This also leads, inter alia, to a corresponding weight of the clamping element itself. The weight of the disc spring assembly is also a significant proportion of the overall weight. Solely the disc spring assembly namely applies the constant forces for bracing and will have a corresponding mass. A typical weight for a clamping element in accordance with said prior art is at least 800 g. This comparatively high weight also has a disadvantageous effect on the bracing action.
If a clamping element of this type is used in nuclear installations which are subject to radiation exposure, a correspondingly great amount of material is also subjected to the radiation and is therefore contaminated by radiation. Clamping elements of this type are thus used, for example, in the case of repair work on heat exchanger tubes in nuclear power stations. It can occur, moreover, that the part shells are contaminated during use. The holding force between the component and the clamping element is then reduced. The clamping element then has to be dismantled and the part shells have to be cleaned correspondingly, which is time-consuming and likewise leads to a correspondingly higher radiation exposure. The radiation exposure of the work which is carried out is subject to checks and is therefore measured.
Proceeding from said prior art, this disclosure describes a clamping apparatus for fixing in a recess, the holding force of which clamping apparatus can be set during operation, and in the case of which clamping apparatus the effect of vibrations on the bracing action is reduced.